Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A storage subsystem coupled to a host computer comprising: a storage device unit for storing data from the host computer; a control unit for controlling a storage area of the storage device; and a memory unit accessed by the control unit; wherein a logical device in the storage device unit is allocated to a virtual logical device provided to the host computer and a user data from the host computer is stored in the logical device of the storage device unit using a page mapping information stored in the memory unit and a track mapping information stored in the storage device unit; the track mapping information is composed of a first track information including a status information and an address information within the logical device and a second track information including a status information and an address information within the virtual logical device; the first track information and the second track information are associated via the address information; and when the first track information or the second track information is abnormal, recovery is performed using an address information in the other track information which is normal.
A storage subsystem connected to a host computer stores data from the host. A controller manages the storage area. Memory accessible by the controller stores page mapping data. A virtual logical device is presented to the host, while actual user data is stored in a logical device on the storage using page mapping data (in memory) and track mapping data (on storage). Track mapping data consists of two parts: first track information (status, address within the logical device) and second track information (status, address within the virtual logical device). These are linked by their address information. If either the first or second track information becomes corrupted, the system recovers using the address from the non-corrupted side.
2. The storage subsystem according to claim 1 , wherein the status information is any one of the following statuses representing a corresponding relationship between the first track information and the second track information, which are an unallocated status, an allocation in progress status, and an allocated status.
The storage subsystem described previously includes status information that indicates the relationship between the first and second track information. This status can be one of three states: "unallocated" (no relationship exists), "allocation in progress" (a relationship is being established), or "allocated" (a valid relationship exists). This status information is used to track the validity of the mapping between the virtual and logical storage locations during data access and recovery operations, as part of the track mapping information.
3. The storage subsystem according to claim 2 , wherein the user data is in either a first data format composed of an address information section within a virtual logical device, a control information section and a data section, or a second data format composed of a data section and a data guarantee code storage section including a preliminary area section.
The storage subsystem described previously stores user data in one of two formats. The first format includes an address within the virtual logical device, control information, and the actual data. The second format contains the data and a data guarantee code storage section that contains preliminary area section. The selection of the data format does not influence the track mapping or data recovery processes, but ensures that all data sectors are self describing with respect to data integrity and data location.
4. The storage subsystem according to claim 3 , wherein the abnormal detection of track information specifies a page and a first track information or a second track information in which failure exists using a failure page bitmap within a logical device, a failure flag of the first track information and a failure flag of the second track information.
The storage subsystem described previously detects abnormalities in track information by using a failure page bitmap (indicating failed pages within a logical device), and failure flags in the first and second track information. This allows the system to pinpoint the specific page and track information (first or second) where the failure has occurred, enabling targeted recovery procedures based on the location and type of failure detected. This ensures the isolation and characterisation of storage failure modes.
5. The storage subsystem according to claim 4 , wherein if abnormality is detected only in the second track information, an area storing the second track information is deleted, a new area storing the second track information is allocated to the deleted area, the status information of the second track information is set to unallocated status, the corresponding second track information based on the address information of the first track information is extracted to recover the corresponding relationship thereof, and then the status information of the second track information is updated to allocated status.
In the storage subsystem described previously, if only the second track information (virtual device address) is detected as abnormal, the system first deletes the corrupted second track information. A new storage area is allocated for the second track information and marked with an "unallocated" status. The system then uses the address from the corresponding first track information (logical device address) to find related second track information and restore the mapping. Finally, the status of the recovered second track information is updated to "allocated", re-establishing the correct virtual-to-logical mapping.
6. The storage subsystem according to claim 4 , wherein if abnormality is detected only in the first track information, an area storing the first track information is deleted, a new area storing the first track information is allocated to the deleted area, the status information of the first track information is set to unallocated status, the corresponding first track information based on the address information of the second track information is extracted to recover the corresponding relationship thereof, and then the status information of the first track information is updated to allocated status.
In the storage subsystem described previously, if only the first track information (logical device address) is detected as abnormal, the system first deletes the corrupted first track information. A new storage area is allocated for the first track information and marked with an "unallocated" status. The system then uses the address from the corresponding second track information (virtual device address) to find related first track information and restore the mapping. Finally, the status of the recovered first track information is updated to "allocated", re-establishing the correct logical-to-virtual mapping.
7. The storage subsystem according to claim 6 , wherein if only the second track information shows a corresponding relationship to the first track information, all the second track information having a same address information as the address information of the second track information are extracted, a first track information is specified using an address information in the data corresponding to the extracted second track information, the specified first track information and the second information are associated, and a status information of a second track information that could not be associated is set to unallocated status.
In the storage subsystem described previously, when recovering a first track (logical device) based on the corresponding second track (virtual device) information, and if only one first track information corresponds to the faulty second track information, the system extracts all second track information entries with the same virtual address. It then uses address information in the stored data associated with each extracted second track information entry to identify a correct first track information entry. The associated first and second track information are then linked, and any second track information that could not be linked is marked as "unallocated".
8. The storage subsystem according to claim 7 , wherein if the number of track information that could be associated is two or more, the logical device storing the track mapping information and the user data is blockaded.
Building upon the previous description of associating first and second track information based on the data's address, if the system finds two or more possible matching track information during the recovery process, it flags a potential data inconsistency. In this scenario, the logical device storing the track mapping information and the associated user data is blockaded. This prevents further data corruption and indicates a need for manual intervention or more sophisticated data recovery techniques.
9. The storage subsystem according to claim 4 , wherein if abnormality is detected in both the first track information and the second track information, the storage area of the first track information and the storage area of the second track information are deleted, a new area is allocated to the deleted area, the status information of the track information is set to unallocated status, and based on the control information and the address information in the data stored in the data storage area, the first track information is associated with the second track information.
In the storage subsystem described previously, if both first track information (logical device address) and second track information (virtual device address) are detected as abnormal, the system deletes both storage areas. New storage areas are allocated and marked "unallocated". The system then uses control information and address data stored within the user data in the data storage area to associate the first track information with the second track information, attempting to rebuild the mapping from available data content.
10. The storage subsystem according to claim 1 , wherein the storage device is composed of a device of one or more types selected from an SSD type device, an SAS type device, or a SAT A type device.
The storage subsystem described previously can use different storage device types. These include one or more of the following: SSD (Solid State Drive), SAS (Serial Attached SCSI) devices, or SATA (Serial ATA) devices. The subsystem architecture is adaptable to these various storage technologies.
11. The storage subsystem according to claim 10 , wherein the storage device includes at least the SSD type device or the SAS type device, and the track mapping information is stored in the SSD type device or the SAS type device.
In the storage subsystem, as described previously where the storage device consists of a combination of SSD, SAS, or SATA type devices, it includes at least one SSD or SAS device. To improve performance, the track mapping information (linking virtual and logical addresses) is stored specifically on the faster SSD or SAS device, prioritizing quick access to metadata during data operations.
Unknown
November 4, 2014
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